Counting apparatus



Jan. 12, 1960 H. E. G'REENHOW COUNTING APPARATUS Filed Feb. 14, 1958United States Patent 2,920,819 COUNTING APPARATUS Henry E. Greenhow,Chingford, London, England, asslgnor to English Numbering MachinesLimited, Enfield, Middlesex, England Application February :14, 1958,Serial No.'715,371

Claims priority, application Great Britain December 9, 1957 4 Claims.Cl. 235-431 This invention relates to counting apparatus.

' It is an object of the invention to provide an improvedcounting-apparatus wherein a unit number wheel, which carries the'lowestorder of digits,wholly or partly encompasses a mechanism for driving thecounting apparatus. ;'It"is another objec't'of the invention to provide'a drivin'gm'echanism permitting a counting apparatus to be I operatedat high speeds whileeliminating the danger of .Wheel is located inposition when the driving shaft is stationary. In such countingapparatus, the inside of the unitinumber wheel is slotted axially toprovide ratchet teeth. The leading edges 'of these slots are sharplyangled to provide engagement for the driving and detent pawls, while thetrailing edges have a more gradual slope so that the detent pawls canreadily disengage from the -slots=wliile-the wheel is rotating. It issometimes difiicult with "such a mechanism to count at high speedbecause the momentum imparted to the unit number wheel may "carry itpast its appropria'telocating points. The driving pawls mayalso bedisengaged entirely from the internal slots of the unit number wheel ifthe driving mechanism is subjected to excessive shock. In either case,the counter "reading may be inaccurate.

Accordingly, it is still another object to provide a counting apparatusin which these shortcomings have been removed.

The tensioning of the pawl springs is sometimes increased to overcomesuch miscounting, but this leads to 'a higher operating torque beingrequired, greater wear between the pawls and the ratchet teeth, andconse quently to a harsh action. The performance and cost of countingapparatus incorporating such ratchet mechanisms Eis also affected by theaccuracy and consistency of the springs used.

It is still a further object to provide a counting apparatus which isinsensitive to variations in the springs used.

It is yet another object of the invention to provide a countingapparatus the driving mechanism of which is not dependent on the use ofindividual detent pawls.

It is yet a further object of the invention to provide a countingapparatus requiring a relatively low operating torque but at the sametime providing a reliable and positive counting operation.

It is still another object of the invention to provide a countingapparatus of simple construction and capable of being quickly and easilyassembled.

These and other objects and advantages of the invenratchet tooth.

rich will become apparent to those skilled in the art from the followingdescription when read in conjunction with the accompanying drawings,which by way of example illustrate a specific embodiment of theinvention and in which:

Fig. 1 is an elevational view, partly in section and partly broken awayof a counting apparatus having a ratchet mechanism;

Fig. 2 is an elevational view, partly in section and partly broken awayshowing the ratchet mechanism of the apparatus of Fig. .1 in a positioncorresponding to the start or finish of a cycle of operation;

Fig. Sis a 'view, corresponding to Fig. 2, but showing the ratchetmechanism in a position just before the end of a ratchet operationstroke;

Fig. 4-is a view similar to Fig. 3, but showing the ratchet mechanism ina position just before the end of a ratchet return stroke; and

Fig. 5 is "a perspective view of the counting apparatus.

A unit number wheel 1 carries numbers about its outer periphery and hasa'counterbore with equally spaced axial slots 2. To an extension member8 of a casing 3 is fixed a stationary first ratchet wheel 4 on the frontface of which are cut equally spaced ratchet teeth 5. Mating I with thestationaryrratchet wheel 4 is an intermediate, second, ratchet wheel 6having projections 7 on its periphery :so shaped and disposed as to be asliding fit in the axial slots 2 in number wheel 1. Across both faces of:the intermediate ratchet wheel 6 there are provided sets-of equallyspaced ratchet teeth 11 and 12, one :set of teeth 11 mating with theteeth 5 on the stationary ratchet wheel "4 and the other set of teeth 12mating with equally spaced ratchet teeth 13 provided on one face of adriving, third, ratchet wheel 14. The driving ratchet wheel 14 has a hub15 acting as a bearing for the intermediate ratchet wheel 5. A drivingspindle 16, is held against axial movement in both directions byretaining clips 24 which engage in grooves 25 provided in the spindle'16. The spindle 16 is fitted with a pin 17 which locates in a slot-likerecess 18 extending from the bore of the-driving ratchet wheel 14. Theopen end of the casing 3 is sealed by a coverplate 21 and the width ofthe gap 23 between the inside face of the coverplate 21 and the rearlofthe driving ratchet wheel 14 is so arranged as to be slightly greaterthan the depth of each ratchet tooth, and appreciably less than twicethe depth of one In this gap, but so arranged as not to reduce itseffective width, is fitted a spring 22 which urges the teeth 'on thethree ratchet wheels into mutual engagement.. The counting mechanism isfitted with two stops 26 provided on the case 3, only one of the stops26 being visible in Fig. l, the stops cooperating with a pin 30 insertedin the spindle 16 so as to restrict the movement of the spindle to anarc of 36 plus a working clearance. A spring 31 is provided forreturning the spindle 16 to its initial position after each operationthereof. By omitting the stops 26 and 27, the pin 3t), and spring 31,

the "counting mechanism may be used for continuous rotary movement witheach digit position indexed by the ratchet mechanism.

Any rotational movement of the driving spindle 16 is transmitted throughthe pin 17 to the driving ratchet wheel 14 whose teeth 13 engage on theintermediate ratchet wheel 6, thus imparting rotary movement to the unitnumber wheel 1 through the peripheral projections 7 on the intermediateratchet wheel 6. During rotational movement of the driving spindle 16,the teeth 11 on the intermediate ratchet wheel 6 slide up the slope ofmating teeth 5 on the stationary ratchet wheel 4 thus imparting axialmotion to the intermediate ratchet wheel 6 and the driving ratchet wheel14 equal to the depth of one ratchet tooth, as permitted by theconnection between the driv- Pat ented Jan. 12, 1960' ing spindle 16 andthe driving ratchet wheel "14'to the extent of the clearance between thecoverplate 21 and the rear of the driving ratchet wheel 14. At theend ofthe rotational movement of the driving spindle 16, the

ratchet teeth are forced into mesh again under thetensionr of the spring22 which urges the three, ratchetv wheels" into mutual engagement. l Q

The driving spindle 16 may be rotated in the opposite direction toreturn to its initial position, under tension of the spring 31 ofsufiicient power to overcome the tension of the spring 22. However, ifdesired,'the.. spring 31 can be omitted, the return of the spindle 16being efiected by external mechanical means. ,Duringj'the returnmovement, the intermediate ratchet .wheelg6 is prevented from rotatingby the mating" teeth on the stationary ratchet wheel 4. The drivingratchet wheel 14 is rotatably connected to the driving spindle 16 by thepin 11 and its ratchet teeth 13 slide. up the slope of the mating teeth12 on the intermediate ratchet wheel 6.until the'initial position of thedriving spindle 16' is reached when the teeth 13 and 12 of the drivingratchet wheel 14 engagement, an outer barrel-shaped unit number wheelhaving at least one axial. slot therein, and at least one projection onthe intermediate "ratchet wheel and disposed about its periphery toprovidelocations for and ensure a sliding fit with saidaxial slot.,

and the intermediate ratchetlwheel 6 respectively are T forced into meshagain underthe pressure of the sprin 22.

. It will be seen that for the unit number wheel'l to overtravel, it isnecessary for the intermediateratchet wheel 6 to rotate beyond themotion imparted to' itiby the driving ratchet wheel 14. Thelte eth onthe intermediate ratchet wheel 6 would then have to slide simulta-'neously over the crests ofthe teeth on boththe driving ratchet wheel 14and the stationary ratchet wheel '4, thus imparting an axial motion tothe driving ratchet wheel 14 equal to at least twice the'depth of" oneratchet tooth. Since this distance is in excess of the gap 23 provided,the intermediate ratchet wheel 6 would be locked axially between thestationary ratchet wheel 4. and the driving ratchet Wheel 14 before ithadrotated through 72. Any momentum separately imparted to' .theintermediate nated before overtravel causing double counting has takenplace."

c It should be clearly understood that the embodiment described andillustrated is given by way of example only;

' Many modifications, omissions and additions .are'possible withoutdeparting from the spirit of the invention.

I claim e 2. A counting apparatus, comprising, a stationary ratchetwheel, radial teeth cut across a front face of said stationary ratchetwheel, an intermediate ratchet wheel adjacent said front face, radial,teeth cut across both faces of said intermediate Vratehet wheel with theteeth on one face directionallyopposed to the teeth on the other face(when looking at ther'espective face), a driv-l ing ratchetwheel,radialfteeth ona fac'of said driving ratchet wheel adjacent saidintermediateratchet wheel,

-r, said radial teeth on said driving ratchet wheel being similar, butdirectionally opposed tofthose on, the -stationary ratchet wheel, a,driving spindle co-axiallycarrying said" stationary, intermediate anddriving ratchet wheels, means connecting said driving'ratchet'wheeltosaid spindle so that the driving ratchetwheel is rotatable with, butaxially displaceable relatively to said spindle, means for securing saidspindle against axial movement relatively to said stationary ratchetwheel, spring meansexerting pressure on said driving ratchet wheel inthe direction towards saidfstationary ratchet wheel for ;urging adjacentratchet teeth on said driving ratchet wheel, saidintermediateratchetwheel and said a stationary ratchet wheel into mutualengagement, a unit number ;wheel,an outer rim forming apart of said num-1 her wheel and surrounding at least in part all of said ratchet wheelscoaxially,and means connecting said number wheel to said intermediateratchet wheel so. that said ratchet wheel 4 and the unit number wheel 1is thus jelimi- T tionary ratchet wheel, an intermediate ratchet wheel,ra-

on said driving ratchet wheel and similar but'direction- '55 allyopposed to those on the stationary ratchet wheel, a hub on said drivingratchet wheel, said hub carrying said intermediate ratchet'wheel, adriving spindle, a pin car 1 'ried by said driving spindle, said pinengaging a slot'in' abore of the driving ratchet, wheel solthat thedriving ratchet wheelrotates with the driving spindle but is allowed tomove axially along the spindle, means for securing the said spindleagainst axial movement, a single number wheel, is rotatable with saidintermediate ratchet wheel andsaid intermediate ratchet wheel is axiallydis-- placeabl'e relativelytosaid number wheel H v I i ;3. Acountingapparatus 'asclaimedin claim2, further including van abutmentcooperating with said driving ratchet wheel and arrangedatadistancetherefronrwhich is greater than the depth of each ratchet toothof said .drivingratchet wheel but less than twice such depth forpreventing overtravel leading to double counting of said unit numberwheel by said driving ratchetwheel abutting against said abutment. e p 44, Accounting apparatus as claimed claim 3, including a casing, and acover plate on said casing, said abutment being formed by said coverplate, said spring means being located between said cover plate and saiddriving ratchet wheel and bearing against said cover plate and ;saiddriving ratchet wheel, f 1 7 References Cited in the file'ofthisipatenta p v UNITED s'rAr s PATENTS, fl i 1,161,171

Vertunni Nov. 2 3, 191s 2,046,810 Cannon July 7, 1936 E QNPA NT t697,257 r Great Britain Sept..16,.1953

